Disazo dye



UNITED- STATES PATENT OFFICE.

THOMAS H. LEAMING, F BUFFALO, NEW YORK, ASSIGNOR '].0 NATIONAL ANILINE & CHEMICAL COMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW Patented Jan. 11, 1921.

YORK. I

DISAZO DYE.

1,365,040, Specification of Letters Patent.

No Drawing.

Buffalo, in the county of'Erie, tate of ew York, have invented certain'new and useful Improvements in hereby declare the following to be a full,

' clear, and exact description of the invention,

such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to a new disazo dye which is of value for dyeing cotton, silk or wool, as well as mixed or union goods composed of these fibers. The invention includes also the dyed fabrics or other materials, dyed with the new dyestufi".

The following specific example will further illustrate the invention, the parts being by weight:

6.9 parts of p-nitranilin are diazotized by dissolving it in 16.8 parts of boiling hydrochloric acid oil-1.19 sp. gin, which has been diluted with 20 parts of water, pouring the boiling solution into 9.6 parts of hydrochloric acid of 1.19. sp. gr., containing sufiicient ice to keep the temperature at 0 (l, and adding parts of sodium nitrite all at once to the resulting cold suspension. It will be understood that the apparatus in which the solution and suspension are made is provided with good agitatin means. The nitrite may beaddedin a solic. form or in a solution of convenient strength; so also, instead of sodium nitrite, other nitrites, such as potassium nitrite can be 'used'. The amount referred to above is based on 100% purity; if less pure an equivalent amount should be used. After the addition of the sodium nitrite, and after the solution has been permitted to stand for a few moments, air is blown through the solution until any excess nitrous acid is expelled, the tempera- 'ture being kept at 0 C. by suitable cooling Disazo Dyes; and I do Application filed February -16, 1920. Serial No. 359,109.

The new dyestufi can be obtained by the .diazotization of acct-.p-phenylcnediamin or of p-nitranilin, coupling the diazo compound so obtained with one molecular proportion of o-anisidin, rediazotizing the resulting monoazo dye, and coupling this secondary diazo compound ,with one molecular proportion of Q-amino-8-naphthol-6-sulfonic acid in alkaline solution, and subsequently sa- -ponifying the acetyl group or reducing the nitro group to give as the final product a dyestufi containing the free amino group.

The new dyestufi has the following probable formula:

dilute hydrochloric acid (approximately 30.

parts of HCl to 1500 parts of water).. This suspension is cooled to from O-to 10f and a concentrated solution of 3.5 parts )i sodium nitrite added with stirring, tht stitring being continued until nitrous acid is no longer present as indicated by testing with starch-iodid paper. g

12 parts of 2-amino-8-naphthol-G-Sulfoniis acid (gamma acid) are dissolved in 175 parts of water containing 40, parts of soda ash,

i and to the resulting cooled solution there is slowly added the secondary diazo'solution produced as above described, the temperature being kept below 10, and the mixture well agitated until coupling is complete. The SO12" on is then heated to about 70 (1.

common. salt added to separate the dyestuii,

and the dytetufi filtered oil'.

The product can be purified by re-solution and reprecipitation to remove any impurities, particularly any red monoazo dye which may be formed as a lay-product. The precipitated dye is then suspended in 3000 parts of water, heated to 70 (1, and a concentrated solution of crystallized sodium sulfid added until the reduction of thenitro group to the amino group is complete, after which the reduced dyestull' is separated from solution by the addition of salt, and dried at about 70 C.

Diazotized acct-p-phenylenediamin may be used in place of diaZotized-pnitranilin, but it is less adval'itageous and requires a relatively] much longer time to couple with o-anisidin; and I regard the process making, use of p-nitranilin as more advantageous and to be recommended.

The dyestufi' produced as above described. in its dried and powdered state, is a brownish black powder soluble in water with a reddish. blue color, giving with hydrochloric acid a reddish brown precipitate and with sodium hyroxid a bluish, black precipitate. It is soluble in alcohol, soluble in concentrated sulfuric acid with a blue-green color niethoxy-p-phenylenediamin and 2.7-diamino-S-naphthol-G-sulfonic acid, and dyeing animal and vegetable fibers, as well as mixtures of such fibers, blue black shades which can be developed on the fiber.

2. The hereindescribed new dye obtainmean so turning blue on the addition of ice and finally giving a red precipitate The dye yields upon reduction with stanno'us chlorid and hydrochloric acid p-phenylenediamin, methoxy-p-phenylcnediamin and 2.7-(ll2l1f1'lino-8-naphthol-(S-s1iltonic acid.

The new dyestull is 1. direct dye, dyeing both vegetable and animal fibers, as well as union fabrics composed of mixed fibers. lt

is therefore applicable to cotton, sillcor wool and to mixed goods composed of these Inaterials. As a direct dye, it yields a fairly bright blue black shade of a reddish tone, which shade may be changed to bright shades of navy blue and various degreeso't' red or greenish blacks by diazotizing on the fiber, and developing with such developers as beta-naphthol, m-toluylenediamin, resorcinol, etc, or mixtures of these. lhe tast-- ness is thereby increased, and; the application value of the product enhanced. The dyestufl is a level dyeing product of good tone and strength, and has good fastness to acids, light and washing.

I claim:

1. The hereindescribed new disazo dye having the following probable,formula:

able by diazotizing the new disazo dye of claim 1 and developing with a developing agent.

3. Materials dyed with the new disazo' 5. Materials dyed with the new disazo' dye of claim 1, said dye being developed or the material,

In testimony whereof I my signature;

THoMas n. LEAMENG. 

